An aboriginal prisoner has died in a detention center in the Australian Northern Territory city of Darwin, amid calls for a probe into reports about torture and mistreatment of indigenous people behind bars in the country.

According to a spokesman for the Darwin Correctional Centre, the 31-year-old man, whose name has not been released in the reports, was found dead in his cell at about 6:30 a.m. local time on Thursday.

The spokesman said the man was a low security prisoner on remand, adding that all attempts by staff at the correctional center to revive him were unsuccessful.

Police are conducting further investigations into the matter.

This comes at a time when mistreatment of aboriginal inmates in Australian prisons has come to the fore after the recent release of a video clip from the Don Dale Youth Detention Center in Australia’s Northern Territory.

The footage, shot between 2010-2014, showed guards beating six teenage prisoners, tear-gassing them, throwing them into cells by the neck, covering their heads with hoods and strapping them naked or half-naked to special chairs.

Reacting to the video, Juan Mendez, the United Nations special rapporteur, expressed concern over the issues, saying, “It’s a very worrisome development that can amount to torture or to cruel, inhuman or degrading treatment under any circumstance.”

The revelations prompted Prime Minister Malcolm Turnbull to order the Royal Commission, the most powerful inquiry in the country, to launch a thorough investigation into the mistreatment of children in detention. He has, however, rejected calls for a broader national inquiry.

Local rights activists say UK-based Amnesty International has already warned Australian authorities about the abuse of minors in the Northern Territory prisons, adding that the government ignored the issue since the teens involved were indigenous.

Although aborigines comprise only three percent of Australia’s population, they represent 27 percent of the country’s prison population and make up a whopping 94 percent of the Northern Territory’s juvenile inmates.

Australia’s nearly 700,000 indigenous citizens track near the bottom of almost every economic and social indicator for the country’s 23 million people.